At 2:21pm today the BBC will be sharing some Sherlock news on its Twitter page.
"It's all gone dark... Something's coming... Or someone. Details coming at 2:21pm tomorrow #221back #Sherlock" is all the information it has given us so far, along with the Moriarty video seen at the end of series three, with the words "Did you miss me?".
We're all feeling really calm about it.
So we came up with a survival plan to get us through until 2:21pm...